(function () {

    var C = (typeof window === 'undefined') ? require('./Crypto').Crypto : window.Crypto;

// Shortcuts
    var util = C.util,
        charenc = C.charenc,
        UTF8 = charenc.UTF8,
        Binary = charenc.Binary;

// Public API
    var SHA1 = C.SHA1 = function (message, options) {
        var digestbytes = util.wordsToBytes(SHA1._sha1(message));
        return options && options.asBytes ? digestbytes :
            options && options.asString ? Binary.bytesToString(digestbytes) :
                util.bytesToHex(digestbytes);
    };

// The core
    SHA1._sha1 = function (message) {

        // Convert to byte array
        if (message.constructor == String) message = UTF8.stringToBytes(message);
        /* else, assume byte array already */

        var m = util.bytesToWords(message),
            l = message.length * 8,
            w = [],
            H0 = 1732584193,
            H1 = -271733879,
            H2 = -1732584194,
            H3 = 271733878,
            H4 = -1009589776;

        // Padding
        m[l >> 5] |= 0x80 << (24 - l % 32);
        m[((l + 64 >>> 9) << 4) + 15] = l;

        for (var i = 0; i < m.length; i += 16) {

            var a = H0,
                b = H1,
                c = H2,
                d = H3,
                e = H4;

            for (var j = 0; j < 80; j++) {

                if (j < 16) w[j] = m[i + j];
                else {
                    var n = w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16];
                    w[j] = (n << 1) | (n >>> 31);
                }

                var t = ((H0 << 5) | (H0 >>> 27)) + H4 + (w[j] >>> 0) + (
                    j < 20 ? (H1 & H2 | ~H1 & H3) + 1518500249 :
                        j < 40 ? (H1 ^ H2 ^ H3) + 1859775393 :
                            j < 60 ? (H1 & H2 | H1 & H3 | H2 & H3) - 1894007588 :
                                (H1 ^ H2 ^ H3) - 899497514);

                H4 = H3;
                H3 = H2;
                H2 = (H1 << 30) | (H1 >>> 2);
                H1 = H0;
                H0 = t;

            }

            H0 += a;
            H1 += b;
            H2 += c;
            H3 += d;
            H4 += e;

        }

        return [H0, H1, H2, H3, H4];

    };

// Package private blocksize
    SHA1._blocksize = 16;

    SHA1._digestsize = 20;

})();
